(2) Kicker S15L7-4 Solo Baric L7 15" Subwoofers+Hifonics Amplifier + Vented Box Square vs. Round: More cone area results in greater sound pressure produced by the woofer. The massive motor structure of the L7 paired with KICKER's patented square-woofer technology provides extreme output capability, Heat-sinking cast aluminum basket provides a strong motor foundation and maintains low temperatures during long-term operation, Injection-molded SoloKon is our most advanced cone design, adding targeted strength for reliable performance and accurate response Venting in the back-bracing of the cone and perimeter of the spider landing provides maximum air-flow to cool the voice-coil during operation. Dual Voice Coils with high-temp copper windings handle extreme power levels for long durations without burning out, T-cut top plate extends the magnetic field of the motor, adding balanced motor strength throughout the entire excursion path of the voice coil 2400W RMS Mono Block Class D Car Amplifier+Bass Remote. Illuminated Hifonics badge, Old School Hifonics Heatsink for Superior Heat Dissipation. Military Grade PCB. SPC - Simpatico Coil Design, HSMD - Hifonics Surface Mount Design. PWM MOSFET Power Supply for Maximum Current Levels, Diagnostic Indicators, DC, Short Circuit, Thermal and Overload Protection Low Level RCA Inputs and Outputs. Frequency Response: 10Hz-300Hz, Signal to Noise Ratio: &gt;95dB, RCA Input. Fuse: 70A x 2, Bass Remote included. THD: % &lt;0.10%, Variable subsonic filter (10-40 Hz), Variable low-pass filter (40-300 Hz). Dimensions: 17.3"L x 2.4"W x 10"H 15" Vented Square Subwoofer Enclosure. Made to work perfectly with Kicker Solo Baric L7, L5, L3, Hifonics square woofers, and other sqaure woofers, Proudly Made In The USA, Using Only The Finest Quality Materials - For The Best Level of Performance From Your Subs! 3/4" USA Heavy Duty MDF Construction. Machine precision cut mounting holes, Top of the line Glue for extra durable adhesion